DESCRIPTION (Adapted from applicant's description): The long-term objective of this research is to define the function of cell-surface carbohydrates during implantation, potentially leading to treatments for some forms of infertility and pregnancy complications. This project is intended to contribute toward the long-term goal by definitively answering whether the H type 1 oligosaccharide hypothesized to mediate embryo adhesion in the mouse is required for implantation. The career development plan of this proposal is directed at promoting scientific independence of the candidate through formal and informal interactions with established investigators in related fields. Adhesion of a mammalian embryo to uterine luminal epithelium is an early step in the series of events leading to implantation. It can be expected that surface-localized molecules displayed by the uterine epithelium and the embryo, are essential to this process. However, the identities and functional attributes of such molecules are poorly understood. Several lines of evidence support the hypothesis that a specific fucosylated carbohydrate epitope, the H type 1 oligosaccharide (Fuc alpha 1-->2Gal beta-), mediates blastocyst adhesion in the mouse. The proposed research will test the hypothesis by altering expression of the enzymes that synthesize fucosylated cell surface molecules, called fucosyltransferases, in uterine epithelial cell cultures and in mutant mice lacking one or more alpha(1,2)fucosyltranferase genes by homologous recombination. The Specific Aims of this project are to: 1) Clone and characterize the genomic sequence of a third murine alpha(1,2) fucosyltransferase that, when compared to the sequence of two previously cloned alpha(1,2)fucosyltransferase genes, will provide a basis for design of alpha(1,2)fucosyltransferase gene-specific probes; 2) Correlate the expression pattern of the alpha(1,2) fucosyltransferase genes during the estrous cycle, early pregnancy, and in ovariectomized mice with the previously determined expression characteristics of the H type 1 oligosaccharide; 3) Test the direct relation of alpha(1,2) fucosyltransferase expression to H type 1 oligosaccharide accumulation in uterine epithelial cell cultures by perturbing alpha(1,2)fucosyltransferase gene expression in vitro; and 4) Test the necessity of the H type 1 oligosaccharide for implantation in mice by eliminating one or more alpha(1,2)fucosyltransferase genes by homologous recombination.